大家在查： ring circles 8-126 欧布排布方式 spherics 约翰·格林利夫 from tempered glass %s.%s ernance 埃曼努尔阿德

乔万尼·卡西尼

In the 17th century , the astronomer Giovanni Cassini noticed Iapetus had one dark side and one lighter side , but had no idea why .